Meter and scale therefor



J. V. SKULLEY METER AND SCALE THEREFOR Sept. 4, 1945.

Filed Feb. 19, 1942 3 Sheets-Sheet l Sept 4, 1945- n J. v. SKULLEY 2,384,350

METER AND SCALE THEREFOR Filed Feb. 19, 1942 3 Sheets-Sheet 2 J. v. SKULLEY 2,384,350

METER AND SCALE THEREFOR Filed Feb. 19, 1942 3 SheetS-Sheef 3 @5275 Jig/@dvi I W- 1 ,/yz fngt@ utilized.

Patented Sept. 4, 1945 9 Claims.

The invention relates generally to indicating devices, and more particularly to meters or the like for measuring and testing electrical circuits.

The invention has among its objects the production of such an indicating device wherein separate graduated scales may be provided for various ranges of the instrument, each scale automatically selecting the proper circuit to produce the range indicated on the particular scale Another object of the invention is the production of such a 'device wherein individual scales may be employed for different types of measurements and tests, thereby enabling the use o f relatively large scales in conjunction with one instrument, and eliminating the necessity ofsepa.- rate instruments for each measurement, or the use of crowdedmultiple scales.

A further object of the invention is the produci tion of a scale and instrument which is so designedv that even an inexperienced operator may readily make measurements and tests, as well as determine the condition of the particular circuit being tested, this result being facilitated by employing a .scale most suitable for the particular measurement, and incorporating suillcient general information relating to such measurement on the back of the scale.

' A further object of the invention is the production of such a device which may beapplied to present instruments and thereby incorporate some of the advantages of the present invention in such instruments. y

Many other objects and advantages of the construction herein shown and described will be obvious to those skilled in the art from the disclosure herein given.

To this end my invention consists in the novel construction, arrangement and combination of parts herein shown and described, and more particularly pointed out in the claims.

Fig. 'l is a front plan view of a scale adapted to be used on existing instruments;

Fig. 8 is a diagrammatic view of the circuit employed in the volt meter illustrated in Figs. 2 and 3; and

Fig. 9 is a similar atlc view of the circuit employed inthe ammeter illustrated in Figs. 2 and 3.

There have been numerous devices on the market for measuring and testing electrical circuits,

particularly automotive circuits and the like.

However in most'instances such instruments have embodied separate meters for each measurement to be made or have utilized meters containing multiple graduations on a single scale, the latter resulting in crowded and more or less illegible scales. Likewise. in the case 4'of multiple range instruments embodying a single multiple scale some form oi' manual switching means must be employed for selecting the various ranges.

In the present invention each series of graduations is on a separate scale member which maybe readily removed from the meter or other instrument. Thus, for each range of th'e instrument a scale member of the most desirable design may be employed. The scale members may contain information yon the back of the same pertaining to' the measurements or tests to be made with that range o! the instrument, together with any other desired infomation such as directions for making repairs, etc. A l

The instrument and scale members are so constructed that insertion of the scale member in the In the drawings wherein like reference characters indicate like or corresponding parts Fig, 1 is a. top plan view of a device embodying the present invention;

instrument will automatically adjust the device for the -particular range indicated on that'scale, eliminating manual selection of the various ranges.

Referring to is illustrated as a volt meter. and 2 indicates generally a second indicating unit illustrated in the present instance as an ammeter, these instruments having indicating needles I and t, respectively. The speciiic construction of these instruments is not shown or described, as the same comprises no part of the present invention. .The units I and I are supported in a vertically extending block Il formed to'receive the respective umts, the latter having terminals I and 'I and a and l, respectively. Extending across the rear face of the block l is a plate la, through which the terminals t, 1, l and l extend,` the latter, and associated wiring, being concealed by a suitably recessed cover member I0.- Extending across the front of the block l is a cover plate lb, having a the drawings I represents generally an indicating unit which in the present instance' portion cut away through which the pointers 3 and 4 extend, and a scale supporting member II provided with scale receiving channels I2 and I 3, the member II having an opening I4 adjacent the front of each unit. Suitable cover means I5 is positioned in front oi each unit, and is provided with transparent portions. I6 through which the respective indicating pointers and scales are visible, the covers I5 being secured to the member II by any suitable means such as screws or the like.

The block 5 is mounted on a base portion, indicated generally by the numeral I1, comprising top and bottom members I8 and I9, respectively, spaced by side members 2| and 22 and end members 23 and 24, all of the members being fastened together by screws, as illustrated, or by other suitable means. Carried by the member I1 is a plurality of resistance elements 25 to 30, inclusive, the latter providing means for increasing the range of the volt meter I. The resistance elements are connected to stationary contacts 3| to 36, inclusive, which are mounted4 on the upper face of the member I8, and cooperating with the respective stationary contacts are movable spring contacts indicated generally by the numerals 31 to 42, inclusive. The stationary contacts 3| to 36A are connected to corresponding ends of the respective resistances by suitable leads, while the movable contacts are connected in parallel to the contact 1 by a conductor 43.

Cooperating with the indicating units are a plurality of scale members, three scale members 44, 45 and 46 being illustrated in Figs. 3, 5 and 6,

, respectively, each of the scale members being in the form of a rectangular plate having a cutaway portion 41 to permit free action-of the indicating pointers, and may be individually positioned in the channels I2 and I3, respectively. Extending from the lower edge of each of the scale members illustrated, is a projection 48, the lattervbeing of a length to close one of the pairs of contacts when the scale member is positioned in its respective channel. The scales may be held in position by any suitable means such as spring elements 49 engageable with the notches 5I) in the respective scales, and to facilitate insertion and removal of the scale members from the instrument, a suitable handle 5I is provided on each member.

It will be apparent that with the scale member 44, the contacts 32--38 will be closed by the engagement of the projection 48 thereof with the spring contact 38. In a similar manner, posi- Vtioning of the scale member 45 in the channel I2 will close the contacts 33-39 to adjust the range of the volt meter I to the corresponding graduations on that scale, and in a similar man-l ner the scale member 4i will close the contacts 3I-31.' The contacts 34 to 36 and 40 to 42 will be respectively closed when the correct scale members (not shown) are inserted in the channel I2, such scale members being similar to those illustrated with the exception that the projec? tions 48 are on the right half of the scale instead of the left, as illustrated.

The circuit connections for the resistance elements 25, 26 and 21, are diagrammatically illustrated in Fig. v8, which circuit is similar to that of the usual multi-range volt meter, andobviously, the connections for the resistance elements 28 to 30 will besimilar to that illustrated for the resistance elements 25 to 21.

It will be apparent that in such a circuit, each pair of contacts places an additional resistor in series with the meter, thereby extending the range of the latter.

The ammeter 2 in the construction illustrated in the drawings is provided with only two ranges, obtained by the use ofA shunts 52 and 53 supported by the upper member Il and connected in series as illustrated in Figs. 3 and 9. Stationary contacts -54 and 55 and movable contacts 58 and 51 operatively connect one or both of the shunts in parallel with ythe ammeter unit 2. 'I'he scale member 58 is provided with a projection similar to projections 43 on the voltmeter scale members for engaging the proper movable contact, while the scale member for the other range of the instrument would be provided with a similar projection for engaging the other movable contact.

The circuit for the ammeter, of the usual type, is illustrated in Fig. 9, and obviously the ammeter or other instrument employed, could be provided with additional ranges if desired by increasing the numberl of pairs of contacts and the number of shunt resistors.

As illustrated in Fig. 6, the back of the scale member may contain infomation regarding the particular range of the instrument obtained by the use of that scale, together with data on tests and measurements to be made with that range, as well assetting forth corrections to be made in the circuits tested to remove defects and the like. For example, if the device was employed in checking automotive ignition circuits, the scale member would contain instructions for making the particular test, as well as correct normal voltages or currents, and set forth how adjustments can `be made to correct low or high readings. This construction is very advantageous,

las it enables a relatively inexperienced person,

may be removably positioned on the meter. The

scale is graduated for the particular range desired and carries on the back face thereof information such as that just described. Obviously, when such scales are used with present meters, it is necessary to manually select the proper meter range to be used with the individual scale.

It will be apparent from the above description that I have provided an indicating device where by the various ranges oi' the instrument may be automatically obtainediby inserting the scale desired, which scales are provided with technical data relating to the tests or measurements -being made. It might be mentioned that, in the above description of my' invention, I have used the terms scale and` "graduation broadly and not in a limited numerical sense, the scale graduations taking any desirable form.

It will also be apparent that while I haveillustrated the invention in connection 'with an ammeter and volt meter, the invention 'may be applied to numerous types of other instruments.

Having thus described my invention, it is 0bvious that various immaterial modifications may be made in the same without departing'from'the parts herein shown and described, or uses men-l tioned. l

What I claim as new and desire to secure b l Letters Patent is:

1. In a device of the kind described the combination oi an indicating unit having an indicating element, a plurality of bodily removable and interchangeable combined scale and switch actuating members, each havinggraduations thereon individually cooperable with said indicating element, means for varying the range of said indieating unit including electric switches, one for controlling each separate range and means carried by each of the respective combined scale and switch actuating members for actuating a switch ofsaid range varying means to provide therange corresponding tothe respective combined scale and switch actuating members, when any one oi the latter is in operative Iposition with respect to the indicating element.

2. In a device of the kind described the combination of an indicating unit, `range varying means including a plurality of switches for varying the measuring capacity oi said unit, a plurality of bodily removable interchangeable cornswitch actuating members adapted to be individually positioned in said channel, each member having graduations thereon individually cooperable with said indicating element, means for varying the range of said indicatingunit, including electric switches, one for each range, and means carried'by the respective combined scale and switch actuating members for actuating a switch of said range varying means when the combined scale and switch actuating member is positioned in said channel to provide therange corresponding to the graduations on such scale member.

6. In adevice of the kind described the combination of an electrical indicating unit having an indicating element, a supporting member for said unit having a channel therein adjacent said element, a plurality of combined scale and switch actuating members adapted to be individually positioned in said channel, each member having graduations thereon individuallyooperable with said indicating element, a plurality of resistance elements for varying the range of said indicating unit, and a plurality of switches for operatively connecting said elements to said unit, each said combined scale and switch actuating member having a switch .actuating element thereon for actuating one of said switches when the scale bined scale and switch actuating members individually cooperable with said unit and switches, said members each having graduations thereon for a respective measuring range of said unit, and having an individual switch actuating element thereon related to the individual graduation and engageable with a selected one of the switches of said first mentioned means to actuate such switch and provide the measuring range of said unit corresponding to the graduations on the respective scale employed.

3. In a device of the kind described the combine-tion of `an electrical indicating unit, a plurality of resistance elements for varying the measuring capacity of said unit, a plurality of switches for operatively connecting said elements to said unit, a, plurality oi selectively interchangeable and removable combined scale and switch actuating members individually cooperable with said unit, said members each having graduations thereon for a respective measuring range of said unit, and means carried by each member and related to the individual scale, said means being engageable with one of said switches to actuate the latter and connect the proper resistance necessaryto provide the measuring range of said unit corresponding to the graduations on the respective scale employed.

4. In a device ofthe kind described the combination of an electrical indicating unit, a plurality of resistance elements for varying the measuring capacity of said unit, a plurality of switches for operatively connecting said elements to said unit, a plurality of removable combined scale and switch actuating members individually cooperable with said unit, said members each having graduations thereon for a respective measuring range of said unit, and a. projection carried by each member engageable with one of said switches to actuate the latter and provide \the, measuring range of said unit corresponding'to the graduations on the respective scale employed.

5. In a device of the kind described the combination of an indicating unit having an indicating element, a supporting member for said unit having a channel therein adjacent said element. a plurality ci interchangeable combined scale and rately, a plurality of interchangeable switch opmember is positioned in said channel to provide the range corresponding to the. graduations on such combined scale and switch actuating member.

7. A member adapted to be positioned across the face of an indicating device having an indicating pointer, said member havinga notch ex-` tending from an edge thereof through which the pointer extends, said notch permitting free movement of said pointer across the race of said meniber, the latter having a plurality of graduations thereon cooperable with such pointer, and a projection extending from one of the edges of said member, adapted to engage and actuate a switch .of the indicating device.

8. In a testing device having a plurality of tes circuits each individually connectible with an indicating member to visibly show the results of each test, the combination of\ a plurality of switches for closing each individual circuit separeceiving each of saidcards individually to releasably hold the same in operative relation to said switches, each of said cards comprising' means for actuating a selected switch, and having calibrations thereon for cooperating with said indicating member to read the direct results 'of said I test as per the-selected circuit. p

9.- In a meter and scale therefor having a. plurality of test circuits each individ ally connectible with an indicating member visiblyshow the results of said test, the combination cfa plurality of switches for closing each individual circuit separately, a. plurality of interchangeable switch operating cards, and guide means for removably receiving each of said cards individually to releasabLv hold they same inoperative relation to said switches, eachof said cards having anotch extending upwardly from-the lower edge thereof through winch the indicating member extends and each of said cards. having a projection for' actuating a selectedswitch and having calibra- 

